Meaning of “I’ll see you in 40”?

Joji makes beautiful music, and this song is no exception. However, a lot of his songs are kinda lacking on the lyrical content IMO. Again, this song is no exception. The lyrics in this song are especially vague. Joji makes a lot of references without giving context (for example the majority of the first [and only] verse). Does this song have a deeper meaning/story?